The disclosure according to the present disclosure relates to a power transmission device including a partitioning member that partitions the inside of a case into a differential chamber where a differential ring gear and a differential gear are placed and a working oil reservoir chamber to reserve working oil.
One known power transmission device mounted on a vehicle includes a tubular portion that covers part of a differential gear and a resinous reservoir plate that has a flange portion extending radially from the tubular portion (refer to, for example, Japanese Patent Application Publication No. 2015-010663). In this power transmission device, in order to catch foreign matter contained in working oil in a working oil reservoir chamber, multiple magnets are mounted on the side surface of the flange portion of the reservoir plate facing toward the working oil reservoir chamber and are circumferentially spaced from each other. Each of the magnets is held by a pair of hook portions that are molded as one piece with the flange portion and that project from the side surface of the flange portion to face each other in a top-bottom direction. The two hook portions facing each other are each elastically deformable in the top-bottom direction and hold the magnet that is fitted therebetween in a direction from the tubular portion toward the flange portion to stop the magnet from coming off.